Modeling Biological and Optical Tools Towards Achieving Deeper Levels of Brain Stimulation using OLEDs

Optogenetics presents the ability to control membrane dynamics through the usage of transfected proteins (opsins) and light stimulation. However, as the field continues to grow, the original biological and stimulation tools used have become dated or limited in their uses. The usage of Organic Light Emitting Diodes (OLEDs) in optical stimulation offers greater resolution, finer control of pixel arrays, and the increased functionality of a flexible display at the cost of lower irradiance power density. This study was done to simulate methods using genetic and optical tools towards decreasing the threshold irradiance needed to initiate an action potential in a ChR2 expressing neuron. Simulations show that pulsatile stimulation can decrease threshold irradiances by increasing the overall duration of stimulus while keeping individual pulse durations below 5 ms. Furthermore, the redistribution of Channelrhodopsin-2 (ChR2) to the apical dendrites and a change in wavelength to 625 nm both result in lower threshold irradiances. However, the model used has many discrepancies and has room for improvement in areas such as the light distribution model and ChR2 dynamics. The simulations run with this model however still present valuable insight and knowledge towards the usage of new stimulation methods and revisions on existing protocols.